So for the easy thing to do.

https://www.amazon.com/LiFePO4-Temperature-Charging-2000-5000-Monitors/dp/B08N56CYS5

The model with the Bluetooth and phone app give give you a way to monitor battery state of charge.

https://www.amazon.com/Victron-Energy-BlueSolar-Charge-Controller/dp/B076N5PTBN/

For a charge controller.

Then search Craigslist for some used 250 watt panels for $50.